Juusan Sai no Tanjoubi, Kougou ni Narimashita.
十三歳の誕生日、皇后になりました。
On her thirteenth birthday, Rian is taken to the Sekisou Kingdom to join the imperial harem. Instead, she is received by Akatsuki, who has legally seized the throne. Declared a suitable match, Rian becomes empress. Despite sharing a bed, Akatsuki treats her as a child and a source of warmth. Each night, he gives her a puzzle to solve in an effort to help her sleep.
